JOPLIN, Mo. - Authorities say at least 89 people have died in the massive tornado that struck the southwest Missouri city of Joplin.

City manager Mark Rohr announced the number at a pre-dawn news conference outside the wreckage of a hospital that took a direct hit from Sunday's storm.

Rohr said the twister cut a path nearly six miles (10 kilometres) long through the centre of town.

Much of the city's south side was levelled, with businesses, homes and restaurants reduced to ruins.